The power output/heart rate relationship in cycling: test standardization and repeatability

Area of Science:

• Sports Science
• Exercise Physiology
• Biophysics

Background:

• The power output/heart rate (PO/HR) relationship is crucial for assessing cycling performance.
• Standardization of PO/HR testing protocols is necessary for reliable physiological data.
• Identifying physiological markers like the heart rate break point aids in performance evaluation.

Purpose of the Study:

• To update and standardize the test for determining the power output/heart rate (PO/HR) relationship in cycling.
• To validate the physiological significance and repeatability of the identified deflection point in the PO/HR relationship.
• To refine incremental cycling test protocols for accurate performance assessment.

Main Methods:

• Development of a laboratory-based protocol using a wind-load cycling simulator.
• Conduction of 500 incremental tests on 290 male cyclists over two years.
• Utilizing subjects' own bicycles with integrated power measurement systems and a progressive cadence increment protocol.

Main Results:

• The PO/HR relationship demonstrated a linear phase at lower outputs and a curvilinear phase at higher outputs.
• A method was developed to mathematically identify the deflection point (heart rate break point) in the PO/HR relationship.
• Test-retest analysis showed no significant differences in heart rate at deflection, power output at deflection, or the slope of the linear PO/HR relationship, indicating high repeatability.

Conclusions:

• The deflection point in the PO/HR relationship is a repeatable physiological phenomenon.
• This phenomenon is not an artifact of the incremental test protocol when using a wind-load simulator.
• The standardized protocol provides a reliable method for determining the PO/HR relationship and its key physiological markers in cyclists.